I voted on the issue linked above. Just wanted to add here that the use case I running up against is styling embedded code snippets from gitlab/github on a blog. The snippets are able to be inserted just fine using an html insert, but I don’t like the default styling I get from those services. You can modify that styling by applying your own css, (see here - Customizing GitHub Gists / Coder's Block) and I can modify the styling by inserting a style tag into the html element in my blog post. I have already tested that and it works. However, this is not maintainable. I don’t want to have to copy paste the same styling information into every single code snippet I add to my blog. That would make it impossible to update the styling for my website. I want to have one css file that I can update and have all of my code snippets change.
If I could link to an external stylesheet from within the page header of the blog page, even that would be workable. But anywhere I try to place a link tag where rel=“stylesheet” wix freaks out.